FreeBSD/Linux Kernel Cross Reference
sys/dev/clock_subr.c

     /*      $NetBSD: clock_subr.c,v 1.27 2016/08/15 15:51:39 jakllsch Exp $ */
     
     /*
      * Copyright (c) 1988 University of Utah.
      * Copyright (c) 1982, 1990, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * the Systems Programming Group of the University of Utah Computer
     * Science Department.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * from: Utah $Hdr: clock.c 1.18 91/01/21$
     *
     *      @(#)clock.c     8.2 (Berkeley) 1/12/94
     */
    
    /*
     * Generic routines to convert between a POSIX date
     * (seconds since 1/1/1970) and yr/mo/day/hr/min/sec
     * Derived from arch/hp300/hp300/clock.c
     */
    
    #if HAVE_NBTOOL_CONFIG_H
    #include "nbtool_config.h"
    #endif /* HAVE_NBTOOL_CONFIG_H */
    
    #ifdef _KERNEL
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: clock_subr.c,v 1.27 2016/08/15 15:51:39 jakllsch Exp $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/errno.h>
    #else /* ! _KERNEL */
    #include <string.h>
    #include <time.h>
    #include <errno.h>
    #endif /* ! _KERNEL */
    
    #include "../sys/clock.h"
    #include <dev/clock_subr.h>
    
    #define FEBRUARY        2
    
    /* for easier alignment:
     * time from the epoch to 2001 (there were 8 leap years): */
    #define DAYSTO2001      (365*31+8)
    
    /* 4 year intervals include 1 leap year */
    #define DAYS4YEARS      (365*4+1)
    
    /* 100 year intervals include 24 leap years */
    #define DAYS100YEARS    (365*100+24)
    
    /* 400 year intervals include 97 leap years */
    #define DAYS400YEARS    (365*400+97)
    
    time_t
    clock_ymdhms_to_secs(struct clock_ymdhms *dt)
    {
            uint64_t secs, i, year, days;
    
            year = dt->dt_year;
    
            /*
             * Compute days since start of time
             * First from years, then from months.
             */
            if (year < POSIX_BASE_YEAR)
                    return -1;
            days = 0;
            if (is_leap_year(year) && dt->dt_mon > FEBRUARY)
                    days++;
    
            if (year < 2001) {
                   /* simple way for early years */
                   for (i = POSIX_BASE_YEAR; i < year; i++)
                           days += days_per_year(i);
           } else {
                   /* years are properly aligned */
                   days += DAYSTO2001;
                   year -= 2001;
   
                   i = year / 400;
                   days += i * DAYS400YEARS;
                   year -= i * 400;
   
                   i = year / 100;
                   days += i * DAYS100YEARS;
                   year -= i * 100;
   
                   i = year / 4;
                   days += i * DAYS4YEARS;
                   year -= i * 4;
   
                   for (i = dt->dt_year-year; i < dt->dt_year; i++)
                           days += days_per_year(i);
           }
   
   
           /* Months */
           for (i = 1; i < dt->dt_mon; i++)
                   days += days_in_month(i);
           days += (dt->dt_day - 1);
   
           /* Add hours, minutes, seconds. */
           secs = (((uint64_t)days
               * 24 + dt->dt_hour)
               * 60 + dt->dt_min)
               * 60 + dt->dt_sec;
   
           if ((time_t)secs < 0 || secs > __type_max(time_t))
                   return -1;
           return secs;
   }
   
   int
   clock_secs_to_ymdhms(time_t secs, struct clock_ymdhms *dt)
   {
           int leap;
           uint64_t i;
           time_t days;
           time_t rsec;    /* remainder seconds */
   
           if (secs < 0)
                   return EINVAL;
   
           days = secs / SECS_PER_DAY;
           rsec = secs % SECS_PER_DAY;
   
           /* Day of week (Note: 1/1/1970 was a Thursday) */
           dt->dt_wday = (days + 4) % 7;
   
           if (days >= DAYSTO2001) {
                   days -= DAYSTO2001;
                   dt->dt_year = 2001;
   
                   i = days / DAYS400YEARS;
                   days -= i*DAYS400YEARS;
                   dt->dt_year += i*400;
   
                   i = days / DAYS100YEARS;
                   days -= i*DAYS100YEARS;
                   dt->dt_year += i*100;
   
                   i = days / DAYS4YEARS;
                   days -= i*DAYS4YEARS;
                   dt->dt_year += i*4;
   
                   for (i = dt->dt_year; days >= days_per_year(i); i++)
                           days -= days_per_year(i);
                   dt->dt_year = i;
           } else {
                   /* Subtract out whole years, counting them in i. */
                   for (i = POSIX_BASE_YEAR; days >= days_per_year(i); i++)
                           days -= days_per_year(i);
                   dt->dt_year = i;
           }
   
           /* Subtract out whole months, counting them in i. */
           for (leap = 0, i = 1; days >= days_in_month(i)+leap; i++) {
                   days -= days_in_month(i)+leap;
                   if (i == 1 && is_leap_year(dt->dt_year))
                           leap = 1;
                   else
                           leap = 0;
           }
           dt->dt_mon = i;
   
           /* Days are what is left over (+1) from all that. */
           dt->dt_day = days + 1;
   
           /* Hours, minutes, seconds are easy */
           dt->dt_hour = rsec / SECS_PER_HOUR;
           rsec = rsec % SECS_PER_HOUR;
           dt->dt_min  = rsec / SECS_PER_MINUTE;
           rsec = rsec % SECS_PER_MINUTE;
           dt->dt_sec  = rsec;
   
           return 0;
   }

Cache object: a5ce5d97b39cbe1c01acd7798a92342a